Loans And Allowance For Credit Losses (Summary Of Past Due Loans (Accruing And Nonaccruing)) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Current Fiscal Year End Date		--12-31
Loans Receivable Held-for-sale, Net		$ 44	$ 172
Current		44,497	42,340
30-89 days past due		140	150
90+ days past due		143	159
Total past due		283	309
Loans and Leases Receivable, Gross		44,780	42,649
Accruing loans 90+ days past due		22	36
Nonaccrual loans that are current	[1]	261	381
Financing Receivable, Recorded Investment, Nonaccrual Status		402	529
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		12	40
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		294	443
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		22,740	21,401
30-89 days past due		90	112
90+ days past due		96	102
Total past due		186	214
Loans and Leases Receivable, Gross		22,926	21,615
Accruing loans 90+ days past due		17	18
Nonaccrual loans that are current		204	345
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		7	9
Loans and Leases Receivable, Gross		2,021	2,019
Financing Receivable, Recorded Investment, Nonaccrual Status		40	36
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		14	10
Loans and Leases Receivable, Gross		2,777	2,645
Financing Receivable, Recorded Investment, Nonaccrual Status		13	11
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		1	1
Loans and Leases Receivable, Gross		185	190
Financing Receivable, Recorded Investment, Nonaccrual Status		0	0
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		116	146
Loans and Leases Receivable, Gross		14,003	13,452
Financing Receivable, Recorded Investment, Nonaccrual Status		195	354
Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		1	0
Loans and Leases Receivable, Gross		364	423
Financing Receivable, Recorded Investment, Nonaccrual Status		8	14
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		69	68
Loans and Leases Receivable, Gross		7,288	6,962
Financing Receivable, Recorded Investment, Nonaccrual Status		90	74
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		0	0
Loans and Leases Receivable, Gross		1,271	778
Financing Receivable, Recorded Investment, Nonaccrual Status		1	1
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		24	31
Loans and Leases Receivable, Gross		9,103	9,322
Financing Receivable, Recorded Investment, Nonaccrual Status		36	29
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		11,093	11,301
30-89 days past due		16	16
90+ days past due		15	24
Total past due		31	40
Loans and Leases Receivable, Gross		11,124	11,341
Accruing loans 90+ days past due		2	13
Nonaccrual loans that are current		25	19
1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		41	34
Loans and Leases Receivable, Gross		6,662	5,891
Financing Receivable, Recorded Investment, Nonaccrual Status		55	36
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		7	7
Loans and Leases Receivable, Gross		597	486
Financing Receivable, Recorded Investment, Nonaccrual Status		0	2
Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		3	3
Loans and Leases Receivable, Gross		509	481
Financing Receivable, Recorded Investment, Nonaccrual Status		0	1
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		10,664	9,638
30-89 days past due		34	22
90+ days past due		32	33
Total past due		66	55
Loans and Leases Receivable, Gross		10,730	9,693
Accruing loans 90+ days past due		3	5
Nonaccrual loans that are current		32	17
Financing Receivable, Recorded Investment, Nonaccrual Status		68	50
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross		660	508
Revolving Credit Facility [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			478
30-89 days past due			2
90+ days past due			1
Accruing loans 90+ days past due			1
Revolving Credit Facility [Member] | Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		506
30-89 days past due		2
90+ days past due		1
Accruing loans 90+ days past due		1
Financing Receivable, Recorded Investment, Nonaccrual Status		0	1
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		44	172
30-89 days past due		0	0
90+ days past due		0	0
Total past due		0	0
Loans and Leases Receivable, Gross		44	172
Accruing loans 90+ days past due		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status		12	40
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			2,010
30-89 days past due			7
90+ days past due			2
Accruing loans 90+ days past due			1
Commercial Real Estate [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		2,014
30-89 days past due		3
90+ days past due		4
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		0	1
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			2,635
30-89 days past due			4
90+ days past due			6
Accruing loans 90+ days past due			1
Home Equity Line of Credit [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		2,763
30-89 days past due		9
90+ days past due		5
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		5	5
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			189
30-89 days past due			1
90+ days past due			0
Accruing loans 90+ days past due			0
Consumer [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		184
30-89 days past due		1
90+ days past due		0
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		0	0
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			13,306
30-89 days past due			72
90+ days past due			74
Accruing loans 90+ days past due			10
Commercial And Industrial [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		13,887
30-89 days past due		60
90+ days past due		56
Accruing loans 90+ days past due		13
Financing Receivable, Recorded Investment, Nonaccrual Status		146	287
Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			423
30-89 days past due			0
90+ days past due			0
Accruing loans 90+ days past due			0
Leasing [Member] | Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		363
30-89 days past due		1
90+ days past due		0
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		8	14
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			6,894
30-89 days past due			40
90+ days past due			28
Accruing loans 90+ days past due			8
Owner Occupied [Member] | Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		7,219
30-89 days past due		29
90+ days past due		40
Accruing loans 90+ days past due		4
Financing Receivable, Recorded Investment, Nonaccrual Status		49	43
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			778
30-89 days past due			0
90+ days past due			0
Accruing loans 90+ days past due			0
Municipal [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		1,271
30-89 days past due		0
90+ days past due		0
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		1	1
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			9,291
30-89 days past due			9
90+ days past due			22
Accruing loans 90+ days past due			12
Term [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		9,079
30-89 days past due		13
90+ days past due		11
Accruing loans 90+ days past due		2
Financing Receivable, Recorded Investment, Nonaccrual Status		25	18
1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			5,857
30-89 days past due			12
90+ days past due			22
Accruing loans 90+ days past due			0
1-4 Family Residential [Member] | 1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		6,621
30-89 days past due		16
90+ days past due		25
Accruing loans 90+ days past due		1
Financing Receivable, Recorded Investment, Nonaccrual Status		27	11
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			479
30-89 days past due			3
90+ days past due			4
Accruing loans 90+ days past due			3
Construction And Other Consumer Real Estate [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		590
30-89 days past due		6
90+ days past due		1
Accruing loans 90+ days past due		1
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 0	$ 0

[1] Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected.